Replaceable contact arms for relays



June 12, 1956 o. s. FIELD REPLACEA-BLE CONTACT ARMS FOR RELAYS Original Filed Oct. 20. 1949 FIC2.2.

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United States Patent Ofiice;

2,750,478 Patented June 12, 1956 REPLACEABLE CONTACT ARMS FOR RELAYS Oscar S. Field, Rochester, N. Y., assignor to General Railway Signal Company, Rochester, N. Y.

Original application October 20, 1949, Serial No. 122,475, now Patent No. 2,617,846, dated November 11, 1952. Divided and this application May 16, 1952, Serial No. 288,282

4 Claims. Cl. 200-166) This invention relates in general to electromagnetic relays, and more particularly pertains to improvements in contact structures for such relays.

This application is a division of my co-pending application Ser. No. 122,475 filed October 20, 1949, now Patent No. 2,617,846 dated November ll, 1952, and entitled Shelf Mounted Plug Coupled Detachable Type Relay.

In the parent application, a structural relay organization is disclosed that is adapted to be mounted on a shelf of any suitable type such as may be found either in a tower or in a relay case along the right of way of a railroad. This structural organization is arranged to have the circuit connections permanently made to its terminals in the usual way provided for shelf relays. On the other hand, the relay operating mechanism of this structural organization is made quickly detachable by the use of plug couplers.

In accordance with the present invention, it is proposed that the relay contact arms be of the type which extend outwardly from the relay and also form a part of the plug coupling structure. It is further proposed that the relay contact arms be made readily replaceable by making them in such a structural form as to readily cooperate with the molded casing of the relay mechanism.

Various other objects, purposes, and characteristic features of the present invention will be in part apparent and in part pointed out as the description of the invention progresses.

In describing the invention in detail, reference will be made to the accompanying drawings in which:

Fig. l is a front view, with certain parts removed, of the relay structural organization embodying the present invention;

Fig. 2 is a fragmentary view of the contact mounting structure employed in the relay operating mechanism;

Fig. 3 is a sectional view of the contact mounting means shown in Fig. 2; and

Fig. 4 is a fragmentary isometric view of a pair of plug coupling elements used to cooperate with the replaceable contacts of the relay mechanism.

In connection with the drawings, it should be understood that they have been made more with the purpose in mind of showing the general structural characteristics of a relay embodying the present invention than for the purpose of showing the details of design of such a relay. For this reason, the drawings include sectional views, and the like, to more clearly show the portions contemplated as constituting the elements of the present invention. It will, of course, be understood that various changes in position, size, and shape may be made to the various elements constituting the structure embodying the present invention without in any way departing from the basic principles involved in the proposed relay structure.

Referring to Fig. 1, it will be seen that the relay structure includes a metal casing having a generally rectangular shape with three enclosed sides and a partially open fourth side. This member 10 is mounted on a base plate 11. A metal plate 13 is mounted over the partially enclosed side of the case 10 to form the front of the relay. The plate 13 is attached by four screws 12. Also, this plate 13 has a suitable opening for receiving the operating mechanism of the relay, as well as two other openings allowing the passage of wires to the plug units 18 and 19 which are attached outside of the case to the plate 13.

The top or cover plate 14 has a large number of holes drilled therein for receiving terminal posts 17 which are held in position by suitable nuts. These posts have sulficiently elongated threaded portions to receive suitable nuts beneath which the terminal wires may be secured and from which these wires extend to the plug coupling units 18 and 19, all in a manner fully disclosed in the parent application.

Referring to Fig. 1 it will be seen that the plug units 18 and 19 are mounted on each side of the central opening within the plate 13, and are secured in positions by bolts 20 and nuts 21. Thus, they are permanently and firmly held in position. Each of these units 18 and 19 includes a plurality of openings for receiving the parts of the plug units which are constructed similarly to those disclosed in the Patent No. 2,457,703, granted December 28, 1948, to J. F. Merkel. Each of these plug units in cludes a plurality of bayonet portions 22 (see Fig. 4) which are placed in position by a pressed fit subsequent to the molding of the unit. Thus, a receiving recess is provided for each of the wire connector elements 23. The wires from the terminals 17 are connected to these connector elements 23 which are snapped into their positions in the recesses so that they cannot be accidentally pulled out. These contact elements may be readily removed by the insertion of a special tool when required.

The two adjacent wire connector elements 23 (see Fig. 4) form opposing resilient spring portions extending beyond the bayonet portion 22 and these spring portions have contact points 27 attached thereto or formed thereon for contacting the rigid fixed fingers 50 of the relay operating mechanism when it is inserted in the opening provided for it. Each pair of connectors 23 are biased apart by the associated bayonet portion 22.

Referring to Fig. 1, a generally rectangular shaped molded base 30 of suitable insulating material is provided within which the core members 31 and 32 of a general U-shape may be mounted. These core pieces 31 and 32 of suitable soft iron are separated sufficiently to permit an armature 33 to be vertically supported on shaft 34 which has both front and back pivot points.

Within the confines of the core members 31 and 32, are located two winding spools and 41 which are of molded material. These winding spools 40 and 41 have the windings of the relay wound thereon with suitable leads extending to fixed contact members, such as 52 shown in Fig. 1. These winding spools have longitudinal passages through their centers to allow for the presence of armature 33 and its relative movement between the ends of the core members 31 and 32.

The relay is polarized by two permanent magnets (not shown). These permanent magnets by reason of their residual magnetism hold themselves in place and act on the armature all in a manner specifically disclosed and described in the above mentioned parent application.

The molded base member 30 has a series of slots and holes along both sides as viewed in Fig. 1. These slots 49 are adapted to receive fixed contact members 50 as shown in the enlarged Figs. 2 and 3. These slots 49 are exactly perpendicular so as to hold the fixed contact members 50 in proper vertical positions as required to cooperate with the movable armature operated contacts 44. The contact fingers 50 have been shown in detail in Fig. 4, where it can be seen, as well as in Fig. 1, that a semi-circular bend is provided at an intermediate point such as to properly locate the contact endwise with respect to the case 30. In

other words, these deformed portions of the contact fingers 50 are so formed as to fit within the circular holes 48; but these circular holes are suitably tapered and are so positioned with respect to the slots 49 for receiving the contact fingers 50, that the circular portion of the contact finger does not actually contact the inner periphery of the holes. Thus, the insertion of the tapered plugs 51 results in firmly securing the fixed contact fingers 50 in place. It is noted that the tapered plugs 51 extend slightly above the surface of the case 30 (see Fig. 3), and are thus accessible so as to be removed to allow the replacement of the fixed contact fingers when this is required. This is a considerable advantage over prior structures Where the fixed contact fingers are permanently molded in the case member, since in that form a whole new structure would be needed to provide for the replacement of any worn fixed contact fingers.

With reference to Figs. 1 and 2, it will be seen that each pair of fixed contact fingers 50 are so located with respect to each other that the tapered plugs 51 tend to move such fingers toward each other and in this way provides a cen tral pressure for the fingers within their slots in such a way as to oppose any pressure applied by movable contacts 44 or by their contact with the plug wire connectors 23 of the plug units (see Fig. 4).

It will be noted that the fixed contact fingers 50 have obliquely bent arms extending at right angles away from its longitudinal axis which serve as inclined planes against which the plug wire connectors 23 may slide into position as the mechanism is moved into place. This use of fixed contacts 50 in pairs provides for equalization of the pressure of the plug contacts on opposite sides of the bayonet member 22. This is repeated, of course, for each pair of fixed contacts. In some instances, such as in the case of fixed contact member 52 of Fig. 1, there is actually no cooperating movable contact, but the fixed contact 52 is employed as an outlet for a winding connection and acts to equalize the pressure on opposite sides of the associated bayonet members 22 of the plug coupling unit.

Having thus described a relay with replaceable type fixed contact arms for use in a plug coupling type relay, it is desired to be understood that this form is selected to facilitate in the disclosure of the invention rather than to limit the number of forms which it may assume; and, it is to be further understood that various modifications, adaptations, and alterations may be applied to the specific form shown to meet the requirements of practice, without in any manner departing from the spirit or scope of the present invention except as limited by the appended claims.

What I claim is:

1. In a relay structure of the type described, a hollow case of molded material, a plurality of rectangular slots around said case adjacent its edge, said slots being open at one side, a cylindrical hole in the same plane but slightly off center with respect to each of said slots, a plurality of contact fingers having rectangular cross-sections of a proper width and thickness to just fit into said slots by insertion through their open sides, and a tapered plug pressed into each of said cylindrical holes to hold said contact fingers in their respective slots.

2. In a relay structure of the type having a casing surrounding a pivoted armature with radially extending movable contacts, the combination of relatively rigid fixed contact arms mounted on said casing for cooperating with said movable contacts and each fixed contact arm having a preformed circular deformation at an intermediate point along its length, a plurality of open sided slots in said casing for receiving said fixed contact arms, said casing having a cylindrical hole formed therein slightly 01f center in each of said slots and extending in the same plane as the associated slot, whereby the positioning of the de formed portion of each contact finger within the hole adjacent its slot longitudinally locates the position of that contact finger, and a tapered pin inserted in each cylindrical hole for securing the fixed contact finger in its respective slot.

3. In a relay structure of the type described, a mechanism casing of molded insulating material, a plurality of open sided narrow slots around said casing, each of said slots having a predetermined depth, a cylindrical hole associated with each slot and located in the same plane but slightly off center With respect to the width of such slot, said hole being slightly deeper than said predetermined depth of said slot, a plurality of contact fingers, one for each slot, each contact finger being of a proper width and thickness to just fit into its respective slot, and a plurality of tapered pins, one for each hole, said pins being pressed into their respective holes to a depth below said predetermined depth of said slots to firmly force said fingers against the sides of their respective slots.

4. In a relay structure of the type having a casing surrounding a pivoted armature with radially extending movable contacts, the combination of fixed contact arms mounted in said casing for cooperating with said movable contacts and comprising a plurality of fixed contact arms each having a circular deformation at an intermediate point along its length, a plurality of slots in said casing for receiving said fixed contact arms, a cylindrical hole located intermediate the length of each slot but slightly off center with respect to its width to allow each slot to receive its respective contact finger with its circular deformation located within the associated hole, said circular deformation in each of said contact arms having an outside radius less than the inside radius of its hole, and a tapered pin for each of said holes, and each having an outside radius approximately the same as the inside radius of said deformation in said contact arm, said pins being inserted in their respective holes for securing the contact fingers in their respective slots.

References Cited in the file of this patent UNITED STATES PATENTS 177,318 Barbour May 16, 1876 2,224,902 Currie Dec. 17, 1940 2,339,354 Rubel et al. Jan. 18, 1944 2,348,088 Nichols et al May 2, 1944 2,437,018 Dodson Mar. 2, 1948 2,543,036 May Feb. 27, 1951 2,547,176 Salmons Apr. 3, 1951 

